The traditional method of administering therapeutic agents to treat diseases of the internal organs and vasculature has been by systemic delivery. Systemic delivery involves administering a therapeutic agent at a discrete location followed by the agent migrating throughout the patient's body including, of course, to the afflicted organ or area of the vasculature. But to achieve a therapeutic amount of the agent at the afflicted site, an initial dose substantially greater than the therapeutic amount must be administered to account for the dilution the agent undergoes as it travels through the body.
At the other end of the spectrum is local delivery, which comprises administering the therapeutic agent directly to the afflicted site. With localized delivery the initial dose can be at or very close to the therapeutic amount. With time, some of the locally delivered therapeutic agent may diffuse over a wider region, but that is not the intent of localized delivery, and the diffused agent's concentration will ordinarily be sub-therapeutic, i.e., too low to have a therapeutic effect. Nevertheless, localized delivery of therapeutic agents is currently considered a state-of-the-art approach to the treatment of many diseases such as cancer and atherosclerosis.
Localized delivery of therapeutic agents can consist of administering a composition containing a therapeutic agent and a targeting moiety designed to interact specifically with a biochemical entity present at, and exclusive to, the afflicted site in the vasculature. A means to administer the compositions without losing a substantial fraction to the systemic circulation or a means to preferentially localize composition components to an endothelium is, however, lacking in the art.
The present invention provides catheter assemblies for delivering therapeutic compositions to an endothelium and methods of using the assemblies for the treatment of vascular disease.